(a) Field of the Invention
The present invention relates to a behind-stop Tesser type lens system.
(b) Description of the Prior Art
Generally, in a Tesser type lens system, the object-side surface of the second lens component has such a shape as to be concave to the object-side in order to correct the spherical aberration generated in the first lens component. Therefore, the incident angle of the offaxial light to this surface will be large and will tend to generate a high-order aberration at the marginal part of the angular field of view. Specially, in the behind-stop type, as the offaxial rays pass the position largely apart from the optical axis compared with the between-stop type, this inclination will be stronger and the curvature of field and a comatic flare will be remarkable.
In order to eliminate this kind of unfavorableness concerning to the aberrations and to maintain a favorable image forming ability, such a method as to make longer the whole length of a lens system was conventionally adopted. Therefore, it was difficult to realize the compactness of a lens system. For example, the lens system disclosed in Japanese laid-open Patent Application No. 22630/75 has such a telephoto ratio as 1.16.